Microsoft have made their Release Candidate 1 of Windows 7 available for download. It will be available until the end of July. To download Windows 7 RC 1, you need to join up to the Customer Preview Program.

Release Candidate 1 will expire on June 1, 2010. Hopefully by that time we should all be using the Final release.

Recommended system specs: a 1GHz processor or faster, DirectX 9-enabled graphics processor with WDDM 1.0+, 1 GB RAM and 16GB of storage for a 32-bit installation, or 2 GB RAM and 20GB of storage for 64-bit.

Both the 32- and 64-bit versions of Release Candidate 1 are available in English, German, Japanese, French, and Spanish.

You can grab the 32 bit version here, or the 64 bit version here.

It should be noted that Release Candidate 1 and later versions will not be able to communicate with “pre-RC computers” remotely, because the default HTTP/HTTPS ports for WinRM and PowerShell have been changed.

If you are currently testing Windows 7 Release Candidate and have a Nvidia graphics card, then you may want to download the latest Beta drivers (v185.81) for Windows 7 that were just released.

The update includes:

• Adds support for the new GeForce GTX 275 GPU.
• Adds support for Ambient Occlusion – the newest NVIDIA Control Panel feature to offer enhanced 3D gaming realism exclusively to GeForce GPUs.
• Adds support for CUDA 2.2 for improved performance in GPU Computing applications. See CUDA for more details.
• Expands GPU hardware acceleration for the NVIDIA Video Encoding library to GPUs with less than 32 cores. Applications using this library include CyberLink PowerDirector 7, Nero Move it 1.5, Loilo SuperLoiloScope MARS, and CyberLink MediaShow Espresso.
• Accelerates performance in several 3D applications. The following are examples of improvements measured with Release 185 drivers vs. Release 181 drivers (results will vary depending on your GPU, system configuration, and game settings):
  • Up to 25% performance increase in The Chronicles of Riddick: Assault on Dark Athena
  • Up to 22% performance increase in Crysis: Warhead with antialiasing enabled
  • Up to 11% performance increase in Fallout 3 with antialiasing enabled
  • Up to 14% performance increase in Far Cry 2
  • Up to 30% performance increase in Half-Life 2 engine games with 3-way and 4-way SLI
  • Up to 45% performance increase in Mirror’s Edge with antialiasing enabled
• Automatically installs the new PhysX System Software version 9.09.0408.
• Supports GeForce Plus Power Pack #3. Download these FREE PhysX and CUDA applications now!
• Numerous bug fixes. Refer to the release documentation notes.
• Users without US English operating systems can select their language and download the International driver here.

You can grab the 32 bit drivers here, or the 64 bit drivers here.

Microsoft have officially confirmed that May 5 is the official public release date for the Windows 7 Release Candidate.

“I’m pleased to share that the RC is on track for April 30th for download by MSDN and TechNet subscribers. Broader, public availability will begin on May 5th,” wrote Microsoft’s Brandon LeBlanc in a corporate blog.

This follows news of a possible Windows XP virtualisation mode which allows Windows 7 to run older software that doesn’t work on Vista or Windows 7 natively. The “WinXP mode” has not been confirmed yet by Microsoft, so consider it a rumour at this stage.